Colored polymers

ABSTRACT

PCT No. PCT/GB96/01776 Sec. 371 Date Feb. 12, 1998 Sec. 102(e) Date Feb. 12, 1998 PCT Filed Jul. 24, 1996 PCT Pub. No. WO97/07169 PCT Pub. Date Feb. 27, 1997A colored polymer obtained or obtainable by polymerization of a mixture consisting essentially of a dye and a triazine compound having at least two groups selected from alkoxymethylamino and hydroxymethylamino. The colored polymers may be used in the coloration of plastics, inks and colored reprographic toners.

This application is the national phase of international applicationPCT/GB96/01776 filed Jul. 24, 1996 which designated the U.S.

This invention relates to coloured filters and to coloured polymers,their preparation and uses in various applications, including thecolouration of plastics, inks and coloured reprographic toners.

U.S. Pat. No. 5,231,135 describes a method for forming a colouredpolymer coating on a substrate, for example an automobile, in which areactive acrylic polymer containing some reactive colourant and alinking agent is applied to the substrate and allowed to cross-link. Thecoatings so formed are used to protect the underlying substrates fromwear and exposure to sunlight and the elements.

We have now found that valuable colorants can be prepared bypolymerisation of certain dyes and triazine compounds. These colorantsare useful for plastics, toners and in particular inks.

According to the present invention there is provided a coloured polymerobtained or obtainable by polymerisation of a mixture consistingessentially of a dye and a triazine compound having at least two groupsselected from alkoxymethylamino and hydroxymethylamino. Preferably thetriazine compound has 2 or 3 groups selected from alkoxymethylamino andhydroxymethylamino. The alkoxymethylamino and hydroxymethylamino groupswhich are present on the triazine compound are preferably of the formula--N(R^(a))(CH₂ OR^(b)) wherein each R^(a) and R^(b) independently is H,alkyl (preferably C₁₋₆ -alkyl), alkoxyalkyl (preferably --(CH₂)_(m)--O(CH₂)_(n) CH₃ wherein m is from 1 to 6 and n is from 0 to 5), aryl(preferably phenyl) or hydroxyalkyl (preferably --(CH₂)_(m) OH wherein mis as hereinbefore defined).

A preferred triazine compound having at least two groups selected fromalkoxymethylamino and hydroxymethylamino is of the Formula (A): ##STR1##wherein R^(c) is alkyl, aryl or preferably a group of formula--N(R^(a))(CH₂ OR^(b)), and each R^(a) and R^(b) independently is ashereinbefore defined.

In a preferred embodiment R^(c) is C₁₋₆ -alkyl, C₆₋₁₂ -aryl orpreferably --N(R^(a))(CH₂ OR^(b)) as hereinbefore defined. Preferablyeach R^(a) is H and each R^(b) is methyl. A particularly preferredtriazine compound is tri(methoxymethylamino)-1,3,5-triazine.

The mixture of said dye and triazine compound may contain smallquantities of other ingredients which are reactive towards the dyeand/or the triazine compound, but it is preferred that the amount ofthese ingredients is less than 20%, preferably less than 10%, morepreferably less than 5% by weight relative to the total weight of dyeand triazine compound. It is particularly preferred that the dye andsaid triazine compound are the only components in the mixture whichpolymerise to form the coloured polymer. In this way, the polymerisationprocess is simplified and the resultant polymer is easy to isolate,formulate, handle and has a strong colour. The mixture may containcomponents which do not form part of the coloured polymer, for example acatalyst or diluents or solvents in which polymerisation takes place.

During polymerisation the dye and the triazine compound react with eachother to give the desired coloured polymer. Thus a dye is chosen whichhas a group which is reactive towards said triazine compound, forexample a --SH, primary amino, secondary amino, hydroxy, epoxide, acid,acid halide, labile ester or an activated vinyl group. Preferably theprimary amino, secondary amino and hydroxy groups are not attached toaromatic carbon atoms because this lowers their reactivity towards saidtriazine compound. Activated vinyl groups are preferably of the formula--COCH═CH₂ or --SO₂ CH═CH₂.

Preferred classes of dyes which may be used are dyes of the azo(preferably monoazo or disazo), azomethine, triphenodioxazine,phthalocyanine, benzodifuranone, anthraquinone, indigoid, polymethinequinophthalone, pyrroline and benzofuranone series, provided of coursethat the dye has a group which is reactive towards said triazinecompound.

A preferred dye is an azo dye which is reactive towards said triazinecompound, especially an azo dye of Formula (1):

    A--N═N--D                                              (1)

wherein:

A is an optionally substituted heterocyclic or carbocyclic group; and

D is an optionally substituted heterocyclic or carbocyclic group or agroup of Formula (2):

    --E--N═N--G                                            (2)

wherein:

E and G are each independently an optionally substituted heterocyclic orcarbocyclic group;

provided that the dye of Formula (1) has a group which is reactivetowards said triazine compound.

When A, D, E or G is a heterocyclic group it is preferably selected fromthienyl, thiazolyl, isothiazolyl, pyrazolyl, benzopyrazolyl, imidazolyl,pyridyl, pyridonyl, thiadiazolyl, furanyl, pyrrolyl, pyridazyl,pyrimidyl, pyrazinyl, benzothiazolyl, benzoisothiazolyl, quinolinyl,isoquinolinyl, indolyl, pyridothiazolyl, pyridoisothiazolyl, triazolyl,pyrrolyl, dioxazolyl, oxazolyl, isooxazolyl, imidazolyl and carbazolyl.When A, D, E, or G is a carbocyclic group it is preferably optionallysubstituted phenyl or naphthyl.

The group A is preferably phenyl, pyrazolyl, thiazolyl, pyrrolyl,indolyl or carbazolyl, more preferably optionally substituted phenyl orpyrazolyl.

When A is optionally substituted phenyl it is preferably of Formula (3):##STR2## wherein: R¹, R² and R³ are each independently H, CN, NO₂, halo,CF₃, --SO₂ R¹⁸, --SO₂ NHR¹⁸, --COOR¹⁸ or --COR¹⁸ ; and R¹⁸ is H,optionally substituted alkyl or optionally substituted aryl.

It is preferred that each of R¹, R² and R³ independently is F, Cl, Br,CN, --SO₂ R¹⁸, --SO₂ NHR¹⁸, NO₂, CF₃, --COOR¹⁸ or --COR¹⁸ in which R¹⁸is as hereinbefore defined.

When A is pyrazolyl it is preferably of Formula (4): ##STR3## wherein:R⁴ is H, --CN, CO₂ H, F, Cl, Br, --COR¹⁸, --CONR¹⁸ R¹⁹, --SO₂ R¹⁸, --SO₂R¹⁸, --SO₂ NR¹⁸ R¹⁹ or --COOR¹⁸ ;

R⁵ is H, aryl, --CN, --CH₂ CN, --SO₂ R¹⁸, alkyl or alkyl substituted by--CN, --CSNR¹⁸ R¹⁹, --SR¹⁸ or --COOR¹⁸ ;

R⁶ is H, alkyl, alkenyl, aryl, --SO₂ R¹⁸, --COR¹⁸ or alkyl substitutedby --CN or --COOR¹⁸ ; and

R¹⁹ is H, optionally substituted alkyl or optionally substituted aryl.

R⁴ is preferably CN, --COR¹⁸, --CONR¹⁸ R¹⁹ or --COOR¹⁸.

R⁵ is preferably phenyl, --CN, or --CH₂ CN.

R⁶ is preferably H or C₁₋₄ -alkyl, especially H.

The group D is preferably optionally substituted phenyl or pyrazolyl.When D is optionally substituted phenyl it is preferably of Formula (5):##STR4## wherein R⁷ and R⁸ are each independently H or optionallysubstituted alkyl or aryl;

R⁹ is H, alkyl, alkoxy, OH, Cl, Br, --COOH, --NHCO-alkyl, NO₂ or--COO-alkyl;

R¹⁰ is H, OH, alkyl, --NR¹⁸ R¹⁹, --NHCOR¹⁸, --NHSO₂ R¹⁸, --NHCONHR¹⁸,--NHCOOR¹⁸ or --NHCO-alkenyl; and

R¹⁸ and R¹⁹ are as hereinbefore defined.

The substituents which may be present on R⁷ and R⁸ are preferablyselected from OH, COOH, --COO-alkyl, CN, phenyl, phenoxy, alkoxy, alkyl,Cl, Br, SH, alkenyl, alkynyl, CHF₂, NH₂, --NH-alkyl, epoxy, --CO-alkenyland --NHCO-alkenyl.

Preferably R⁷ and R⁸ are each independently optionally substituted C₁₋₁₀-alkyl, more preferably C₁₋₈ -alkyl or C₁₋₆ -hydroxyalkyl and especiallya-branched C₁₋₈ -alkyl or C₁₋₆ -hydroxyalkyl.

R⁹ is preferably H, C₁₋₄ -alkyl, C₁₋₄ -alkoxy, NO₂, COOH or --COO(C₁₋₄-alkyl), more preferably H, OCH₃, NO₂, CH₃, COOH or COOCH₃.

R¹⁰ is preferably H, C₁₋₄ -alkyl or --NHCO(C₁₋₄ -alkyl), more preferablyH, CH₃ or --NHCOCH₃.

When D is pyrazolyl it is preferably of Formula (6): ##STR5## wherein:R¹¹ is H, alkyl or aryl;

R¹² is NH₂ or --NH-alkyl; and

R⁶ is as hereinbefore defined.

R¹¹ is preferably H or C₁₋₄ -alkyl, more preferably C₁₋₄ -alkyl.

R¹² is preferably NH₂ or --NH-(C₁₋₄ -alkyl), more preferably NH₂.

E is preferably optionally substituted phenylene, thienyl orisothiazolylene, especially phenylene of Formula (7): ##STR6## wherein:R¹³ is H, OH, alkoxy, alkoxyalkoxy, --NHCOR¹⁸ or --NHSO₂ R¹⁸ ; and

R¹⁴ is H, alkyl-NHCO-alkyl or --NHCO-aryl.

R¹³ is preferably H, C₁₋₆ -alkoxy or C₁₋₆ -alkoxy-C₁₋₆ -alkoxy.

R¹⁴ is preferably H, OH, C₁₋₆ -alkyl, --NHCO(phenyl) or --NHCO(C₁₋₆-alkyl)

The group G is preferably optionally substituted phenyl or pyrazolyl,especially of Formula (5) or Formula (6).

When a group represented by R¹, R², R³, R⁵, R⁶, R⁹, R¹⁰, R¹¹, R¹², R¹³,R¹⁴, R¹⁸ or R¹⁹ is or contains an alkyl or alkoxy group it is preferablyC₁₋₆ -alkyl or C₁₋₆ -alkoxy.

Where a group represented by R⁵, R⁶, R⁷, R⁸, R¹¹, R¹⁸ or R¹⁹ is orcontains an aryl group, the aryl group is preferably a phenyl ornaphthyl group, more preferably a phenyl group.

Where a group represented by R⁶, R⁷, R⁸, R¹⁰ is or contains an alkenylgroup it is preferably C₂₋₆ -alkenyl, especially vinyl or allyl.

Where a group represented by R⁷ or R⁸ contains an alkynyl group it ispreferably C₂₋₆ -alkynyl.

The alkyl or alkoxy group or substituents containing alkyl or alkoxygroups represented by any one of R, R¹ to R³ and R⁵ to R¹⁴, R¹⁶, R¹⁸ andR¹⁹ may be straight or branched chain.

When any of the groups represented by A, D, E, G and R¹ to R³, isoptionally substituted the substituents are preferably selected from F,Cl, Br, I, NO₂, CN, CF₃, --SO₂ F, --OR¹⁸, --SR¹⁸, --NR¹⁸ R¹⁹, --COOR¹⁸,--SO₂ R¹⁸, --COR¹⁸, --SO₂ NR¹⁸ R¹⁹, --CONR¹⁸ R¹⁹, --NHCOR¹⁸, --NHSO₂R¹⁸, --NHCOOR¹⁸, C₁₋₆ -alkyl and C₁₋₆ -alkoxy in which R¹⁸ and R¹⁹ areas hereinbefore defined.

Where R¹⁸ and R¹⁹ is optionally substituted the substituents arepreferably selected from F, Cl, Br, NO₂, CN, CF₃, SO₂ F, OPh, OC₁₋₆-alkyl and C₁₋₆ -alkyl.

Especially preferred azo dyes are of Formulae (8) and (9): ##STR7##wherein: R¹⁵ is H, C₁₋₄ -alkyl, phenyl, C₁₋₄ -cyanoalkyl or --CN;

R¹⁶ is C₁₋₄ -alkyl;

R¹⁷ is H or phenyl; and

R⁶, R⁷ and R⁸ are as hereinbefore defined.

A specific example of a dye of Formula (8) is Dye 1 in which R¹⁵ is--CN, R¹⁶ is t-butyl and R¹⁷ is phenyl.

Specific examples of dyes of Formula (9) are Dye 2 in which R⁶ is --H,R⁷ is ethyl, R¹⁶ is methyl, R⁸ is ethyl and R¹⁵ is --CN; and Dye 3 inwhich R⁶ is --H, R⁷ is ethyl, R¹⁶ is methyl, R⁸ is 1-methylpropyl andR¹⁵ is phenyl.

A preferred dye of the phthalocyanine series is of Formula (10):

    MPc[XR.sup.20 ].sub.n                                      (10)

wherein:

M is H, Si, Ge, metal, oxymetal, hydroxymetal or halometal;

Pc is a phthalocyanine chromophore;

X is a divalent heteroatom or a divalent linking group;

R²⁰ is H or a substituent; and

n is from 1 to 16;

provided that the dye of Formula (10) has a group which is reactivetowards said triazine compound.

The species M is preferably selected from H, a transition metal, ahalometal, Si or Ge and more preferably H, Ni, Cu, Mn, Fe, Sn, Co, Ti,V, (halo)Al (e.g. as Al(Cl)), (halo)In (e.g. In(Cl)), Si and Ge,especially Cu or Ni.

The group X is preferably O or S or a group containing one or a pair oflinked heteroatoms selected from N, O and S, especially --NR--,--CO.O--, --SO₂.O--, --SO₂ --, --SO₂.NH--.

Where R²⁰ is other than H it is preferably selected from alkyl,especially C₁₋₄ -alkyl; aryl, especially phenyl; epoxy, --CO-C₂₋₆-alkenyl, especially acryloyl; --NHCO-C₂₋₆ -alkenyl, especiallyacryloylamido; or, where X is NR, R and R²⁰ may be linked to form, withthe N atom, a 5-, 6- or 7-membered heterocycle.

The value of n is preferably from 1 to 8, more preferably from 1 to 4and especially 2, 3 or 4. A preferred phthalocyanine is atetra(sulphonamido)phthalocyanine, especially one in which X is --SO₂NH-- or --S-- and R²⁰ is selected from C₁₋₄ -hydroxyalkyl, C₁₋₄-aminoalkyl and C₁₋₄ -carboxyalkyl.

Preferably the group which is reactive towards the triazine compounds isisolated from the chromophore, for example by an alkylene group, becausethe reaction of this type of dye with the polymer precursor does notcause any appreciable change in colour.

Dyes used in the present invention may be prepared by conventionalmeans, for example the monoazo and disazo dyes may be formed bydiazotisation of an amine and coupling.

Phthalocyanines of Formula MPc(XR²⁰)_(n) may be prepared by procedureswhich are analogous to those known in the art, for example by heatingcopper phthalocyanine with chlorosulphonic acid, then with phosphoruspentachloride, to form copper phthalocyanine tetra(sulphonylchloride),followed by condensation with an amine having groups which are reactivetowards said triazine compound. The condensation can be performed in aliquid medium if desired, e.g dioxane.

Further examples of dyes which can be used in the mixtures to form acoloured polymer are described in U.S. Pat. No. 5,231,135, structures A(in Table 1) to V inclusive, which are incorporated herein by referencethereto.

Polymerisation of the mixture comprising a dye and said triazinecompound is preferably initiated thermally or chemically, for example byheating the mixture. Preferred thermal initiation comprises heating themixture to a temperature sufficient to induce polymerisation of the dyeand triazine compound, preferably from 40° C. to 250° C., morepreferably from 50° C. to 200° C., and especially from 50°-100° C.

The ratio of dye to said triazine compound in the mixture depends ontheir relative molecular weights and the number of reactive groups eachcontains. Preferably the ratio of dye and said triazine compound byweight lies in the range 1:0.1 to 1:10, more preferably 1:0.5 to 1:2.5.

The polymerisation is preferably performed in a solvent or diluent,especially water or an organic solvent, for example an alkanol or analiphatic ketone, or a mixture comprising water and an organic solvent.In a preferred process, a solution of the dye and the triazine compoundin a solvent is heated, preferably at the aforementioned temperatures,and the coloured polymer precipitates from the solution and iscollected. The precipitate may be collected by any convenient means, forexample by filtration.

The polymerisation is preferably performed at a pH below 7, for exampleat a pH of from 2.5 to 5, preferably from 3 to 4. Any unreacted startingmaterial may be removed from the product by washing. Unreacted triazinecompound may be removed from the coloured polymer by washing with anorganic solvent, for example acetone, and unreacted water-soluble dyemay be removed from the coloured polymer by washing with water or dilutealkali, for example dilute sodium hydroxide solution.

The coloured polymer obtainable by the process described above is highlyinsoluble and consequently analysis to determine its chemical structureis not easy. Without wishing to restrict the scope of the presentinvention by limitation to any theory, however, it is probable that thepolymer comprises units of various sizes in which up to ten or morereactant molecules are linked together. Thus for example, a dye havingtwo --CH₂ CH₂ OH groups could react with two trimethoxymethylmelaminemolecules, then the two free --NHCH₂ OCH₃ groups on each triazine ringcan react with further molecules of the dye, then newly added dyemolecules can react with further molecules of trimethoxymethylmelamine,and so on until a coloured polymer results containing dye molecules ontriazine rings linked by --NHCH₂ OCH₂ CH₂ -- groups.

The coloured polymer provided by the invention has a number of possibleapplications. The polymer may be used for colouring plastics, inks forwriting and printing or as a constituent of a colour toner for use inelectrophotography. The coloured polymer can be readily dispersed inorganic and aqueous media. This invention has an advantage overconventional pigments in that it can be used to provide a wider varietyof colours.

According to a further aspect of the present invention there is providedan ink comprising a liquid medium and particles dispersed therein of acoloured polymer obtained or obtainable by polymerisation of a mixturecomprising or consisting essentially of a dye and a triazine compoundhaving at least two groups selected from alkoxymethylamino andhydroxymethylamino.

The coloured polymer obtained or obtainable by polymerisation of amixture comprising or consisting essentially of a dye and said triazinecompound is preferably in particulate form and has a particle size ofless than 15 microns, more preferably 0.01 to 10 microns, especially0.04 to 5 microns, more especially 0.05 to 1 mm, particularly 0.05 to0.3 microns. These sizes are preferred to enable the coloured polymerparticles to pass through ink jet printer nozzles which typically have adiameter of 10 to 50 microns.

When the particles of coloured polymer are obtained or obtainable bypolymerisation of a mixture comprising a dye and said triazine compoundthe mixture may contain other ingredients which are reactive towards thedye and/or the triazine compound. Examples of such other ingredients aredescribed below as film-forming ingredients and film-forming resins.However, it is preferred that the mixture consists essentially of a dyeand said triazine compound because the resultant coloured polymer iseasier to prepare, isolate, formulate, handle and has good intensity ofcolour.

The ink preferably contains from 0.5% to 20%, more preferably from 0.5%to 15%, and especially from 1% to 5%, by weight of coloured polymer(s)based on the total weight of the ink. The ink may contain more than onecoloured polymer, for example two or three such polymers.

The liquid medium is preferably an organic solvent or, more preferably,water or an aqueous medium comprising a mixture of water and one or morewater-soluble organic solvents, preferably in a weight ratio of water tothe solvent(s) from 99:1 to 1:99, more preferably from 95:5 to 50:50 andespecially from 90:10 to 60:40.

Each water-soluble organic solvent is preferably a C₁₋₄ -alkanol, e.g.methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol,tert-butanol or isobutanol; an amide, e.g. dimethylformamide ordimethylacetamide; an ester, e.g. diacetine; a ketone or ketoalcohol,e.g. acetonemethylethylketone, methylisobutyl ketone or diacetonealcohol; an ether, e.g. tetrahydrofuran or dioxane; a polyalkyleneglycol, e.g. polyethylene glycol or polypropylene glycol preferablyhaving molecular weights up to 1000 and especially from 100 to 500; analkylene glycol containing 2 to 6 carbon atoms, e.g. ethylene glycol,propylene glycol, butylene glycol or triethylene glycol or diethyleneglycol and thioglycol and the diglycol equivalent thereof; a polyol e.g.glycerol or 1,2,6-hexanetriol; a lower alkyl ether of a polyhdricalcohol, e.g. 2-methoxyethanol, 2-[2-(2-methoxyethoxy)ethoxy]ethanol or2-[2-(2-ethoxyethoxy)-ethoxy]-ethanol; a heterocyclic ketone, e.g.2-pyrrolidone or N-methylpyrrolidone. The liquid medium preferablycontains from 1 to 5 water-soluble organic solvents, more preferably 1,2or 3 such solvents.

Preferred water-soluble organic solvents are selected from heterocyclicketones, especially 2-pyrrolidone and N-methylpyrrolidone; alkyleneglycols or lower alkyl ethers of polyhydric alcohols, especiallyethylene glycol, diethylene glycol, triethylene glycol and2-methoxy-2-ethoxy-2-ethoxyethanol; and polyethylene glycols having amolecular weight from 100 to 500. A preferred specific solvent mixtureis a binary mixture of water and either diethylene glycol, 2-pyrrolidoneor N-methylpyrrolidone in a weight ratio as mentioned above.

Examples of suitable ink media are given in U.S. Pat. No. 4,963,189,U.S. Pat. No. 4,703,113, U.S. Pat. No. 4,626,284 and EP 425,150A.

When the liquid medium is water or an aqueous medium it preferablycontains a hydrophillic surfactant which assists dispersion of thecoloured polymer. Suitable dispersants include aromatic species having ahydrophillic chain, for example a poly(alkyleneoxy) chain; homo- orhetero-poly(alkylenenoxylates); lignin sulphonates; andformaldehyde-arylsulphonic acid adducts.

The liquid medium may also be an organic solvent which may be more orless polar depending upon the nature of the substrate and theperformance requirements of the ink. Such non-aqueous inks preferablycontain a dispersant to assist stabilisation of the dispersed colouredpolymer. Suitable dispersants include those having polyester and/orpolyether chains having an affinity for organic solvents liquids andgroups which have an affinity for the coloured polymer. Examples of suchdispersants include SOLSPERSE 13000, preferred in non-polar solvents,and SOLSPERSE 24000, preferred in more polar media (e.g. esters andketones).

Preferably the ink also contains a film-forming resin or film-formingingredients, especially an air-curable or thermally curable film-formingresin, to improve the adhesion of the coloured polymer to substrates.The preferred film-forming resin will depend upon the nature of theliquid medium, different types of resins being generally employed foraqueous and non-aqueous liquid media.

Preferred film-forming resins for use in water and inks aqueous areair-curable acrylics (e.g. the NEOCRYL resins) and photo-curablepolyesters or urethanes (e.g. the NEORAD resins).

Preferred film-forming resins for use in non-aqueous inks are alkydresins (air-curable or isocyanate curing) e.g. those sold under the nameSYNOLAC, thermosetting acrylics (e.g. SYNACRYL), urethanes(thermosetting) e.g. those sold under the name UNITHANE, and polyesters(thermosetting) e.g. those sold under the name SYNOLAC. To prepare theink, the coloured polymer is preferably pulverised and dispersed in theliquid medium, preferably in the presence of a surfactant.

The film-forming ingredients preferably comprise a mixture of an organicmonomer, comonomer, pre-polymer, uncured polymer or copolymer andmixtures thereof which is capable of polymerisation and/orcross-linking. Where mixtures of different polymer precursors are used,preferably at least one of the polymer precursors is capable of reactingwith the coloured polymer. Examples of polymer precursors includeacrylates, methacrylates, acrylamides, methacrylamides, epoxides,esters, urethanes, isocyanates, alcohols, vinylalcohols, imides, amides,phenols, acetates, carbonates and their derivatives, amines, carboxylicacids and orthoformaldehyde condensates, polyacrylic resins,polyvinylalcohol resins, melamine formaldehyde resin condensates, alkydresins, epoxy resins, polyimides, polyamide resins, phenolic resins,polyester resins, polyvinylacetate, polycarbonate resins, urethaneresins and their derivatives and copolymers.

The film-forming ingredients preferably include one or more componentsselected from acrylamides, epoxides, epoxy resins, acrylamide/epoxyresin systems, melamine formaldehyde resin condensates, polyester, alkydresins, hydroxylated or carboxylated acrylics, hydroxylatedacrylic-melamine formaldehyde systems and especially fromacrylamide/epoxy resin systems and hydroxylated acrylic-melamineformaldehyde systems.

Polymerisation of the film-forming ingredients is preferably caused bychemical, photochemical, or thermal means, as discussed above inrelation to preparation of the colour polymer. Preferably curing isthermal, the conditions being as described above for the preparation ofthe coloured polymer.

The ink may further contain one or more pigments for modifying the shadeof the inks. However, where the coloured polymers are characterised bystrong, bright, fast shades, it is preferred not to incorporate pigmentswhich will detract in any way from these desirable properties.

A further feature of the invention provides a process for thecolouration of a substrate comprising applying thereto an ink or acoloured polymer according to the invention.

The ink may be applied to a substrate by a printing process, preferablyby a flexographic, off-set lithographic, gravure, intaglio, ink-jet orscreen printing processes, especially by ink jet printing. The resultantprints have bright, strong images with good fastness properties. Theprinciples and procedures for ink jet printing are known in the art, forexample in High Technology Applications of Organic Colorants, P.Gregory, Chapter 9 ISBN 0-306-43637-X.

Suitable substrates are transparent or opaque, for example paper, whichmay be plain or treated to enhance the properties of the ink thereon,textiles and overhead projector slides. The present ink has theadvantage of giving good performance even on substrates which have notbeen subjected to any special pre-treatments.

In a further aspect, the present invention provides a process forpreparing an optical filter comprising applying a red, green and/or bluean ink according to the invention to a transparent substrate, preferablyby a printing process, especially by an ink jet printing process, in apattern suitable for a colour filter. Preferably the ink containsfilm-forming ingredients described above.

Preferably the transparent substrate is glass or plastic, and preferablythe printing process comprises ink-jet printing.

Optical filters, also known as colour filters, are used in liquidcrystal displays, for example those used in small television receivers.

A preferred process for preparing an optical filter comprises the stepsof:

(a) forming a plurality of discrete filter regions on a transparentsubstrate wherein at least one of the regions is coloured using a red,green or blue ink according to the invention; and

(b) heating or ageing the product of step (a) thereby removing theliquid medium from the ink.

The discrete filter regions described in step (a) can be formed byapplying a uniform coating of the ink on the substrate and subsequentlyremoving some of the ink to give the desired filter region.Alternatively the discrete filter regions can be formed by applying theink in the desired pattern on the substrate, preferably by an ink jetprinting process.

The preferred optical filter comprises a transparent substrate bearingtriads consisting of a red, green and a blue elements.

Where the process used for forming the discrete filter regions on thesubstrate is ink-jet printing, it is possible to achieve printing of allthree primary colours (red, green and blue) simultaneously to formtriads or any desired grouping of filter elements.

The invention is further illustrated by the following Examples.

EXAMPLE 1

Preparation of Coloured Polymer

A solution of a phthalocyanine dye (0.1 g) having the followingstructure: ##STR8## and tri(methoxymethylamino)-1,3,5-triazine (90% inbutanol; 0.25 g) in water was adjusted to pH 3-4 using concentratedhydrochloric acid and warmed to 50-55° C. for a period of 45 minutes.During this time, a coloured polymer precipitated from solution. Aftercooling, the coloured polymer was filtered-off. The coloured polymer wastwice vigorously agitated with dilute sodium hydroxide solution toremove unreacted dye, washed with cold water, then vigorously agitatedwith acetone to remove any excess triazine compound, collected, anddried to give 0.2 g of a coloured polymer having a bright cyan colour.

Ink Preparation

The coloured polymer (1 g) was dispersed in water (3.5 ml) in thepresence of a surface-active agent comprising abeta-naphthol-polyethylene oxide adduct (0.5 g), using glass beads (5 mmdiameter) and a laboratory shaker. The resultant ink was bar-coated ontopaper giving a bright cyan print which showed instant 100%water-fastness.

EXAMPLES 2 TO 4

Following the general procedure described in Example 1, further colouredpolymers were prepared by reaction oftri-(methoxymethylamino)-1,3,5-triazine with dyes of the followingformulae:

    ______________________________________                                           Formula (11)                                                                ##STR9##                                                                        -                                                                          Example         Q                                                             ______________________________________                                        2               p-C.sub.6 H.sub.4.OCH.sub.2 CH.sub.2 OH                         3 m-C.sub.6 H.sub.4.SO.sub.2 NHCH.sub.2 CH.sub.2 OH                           4 m-C.sub.6 H.sub.4.SO.sub.2 N(CH.sub.2 CH.sub.2 OH).sub.2                  ______________________________________                                    

EXAMPLES 5 TO 7

The method of Example 1 was repeated except that in place of thephthalocyanine dye there was used dyes of formula 12, 13, 14: ##STR10##

We claim:
 1. A colour filter or reprographic toner which comprises acoloured polymer corresponding to the polymer obtained by polymerisationof a mixture comprising a dye and a triazine compound having at leasttwo groups selected from the class consisting of alkoxymethylamino andhydroxymethylamino.
 2. A colour filter or reprographic toner accordingto claim 1 wherein the dye is selected from the group consisting of dyesof the azo, azomethine, triphenodioxazine, phthalocyanine,benzodifuranone, anthraquinone, indigoid, polymethine, quinophthalone,pyrroline and benzofuranone series and the dye has a group which isreactive towards the triazine compound.
 3. A colour filter orreprographic toner according to claim 1 wherein the triazine compound isof the Formula (A): wherein R^(c) is selected from the group consistingof alkyl, aryl and substituents of formula --NR(R^(a))(CH₂ OR^(b)); andeach R^(a) and R^(b) independently is selected from the group consistingof H, alkyl, alkoxyalkyl, hydroxyalkyl and aryl.
 4. A colour filter orreprographic toner according to claim 1 wherein the triazine compound istri(methoxymethylamino)-1,3,5-triazine.
 5. A colour filter orreprographic toner according to claim 1 wherein the coloured polymer isin particulate form having a particle size of less than 15 microns.
 6. Acolour filter or reprographic toner according to claim 1 which furthercontains a film-forming resin or film-forming ingredients.
 7. A processfor preparing a colour filter according to claim 1 comprising applying ared, green and/or blue ink comprising a liquid medium and particlesdispersed therein of a coloured polymer corresponding to the polymerobtained by polymerisation of a mixture comprising a dye and a triazinecompound having at least two groups selected from the class consistingof alkoxymethylamino and hydroxymethylamino to a transparent substratein a platen suitable for a colour filter.
 8. A process for preparing anoptical filter according to claim 1 comprising the steps of:(a) forminga plurality of discrete filter regions on a transparent substratewherein at least one of the regions is coloured using a red, green orblue ink comprising a liquid medium and particles dispersed therein of acoloured polymer corresponding to the polymer obtained by polymerisationof a mixture comprising a dye and a triazine compound having at leasttwo groups selected from the class consisting of alkoxymethylamino andhydroxymethylamino; and (b) heating or ageing the product step of (a)thereby removing the liquid medium from the ink.
 9. A process accordingto claim 8 wherein the ink is applied to the substrate by an ink jetprinting process.
 10. A colour filter or reprographic toner according toclaim 1, wherein the mixture from which the coloured polymer is obtainedcomprises no more than 20% (relative to the total weight of the dye andthe triazine compound) of other ingredients which are reactive to thedye and/or the triazine compound.
 11. A colour filter or reprographictoner according to claim 1, wherein the coloured polymer is obtained bypolymerisation of a mixture consisting essentially of a dye and atriazine compound having at least two groups selected fromalkoxymethylamino and hydroxymethylamino.
 12. In a method involving theuse of a reprographic toner, the improvement wherein said toner is oneaccording to claim
 1. 13. An ink comprising a liquid medium andparticles dispersed therein of a coloured polymer corresponding to thepolymer obtained by polymerisation of a mixture comprising a dye and atriazine compound having at least two groups selected from the classconsisting of alkoxymethylamino and hydroxymethylamino wherein the inkcomprises from 0.5% to 20% of the coloured polymer based on the totalweight of the ink; and the coloured polymer has a particle size of lessthan 15 microns.